How do the baby respiration and circulation change when the baby is born?

Answer 1

Fetus does not need to go for respiration in the womb of the mother. It gets the oxygen and food from the blood of the mother. The carbon bi oxide and metabolic waste products are carried away via the blood of the mother only. So blood does not need to pass from the lungs of the fetus. The blood pass from right atrium to left atrium via a hole in the wall between the two atria. This is a short cut. The very great pressure from unopened blood vessels of the lungs prevent the flow through lungs. After the birth of the child the umbilical cord is tied up. The newborn neither gets oxygen nor the carbon bi oxide is carried away from the body. The accumulated carbon bi oxide stimulates the respiratory center of newborn. As the newborn takes in a deep respiration, air enters in the lungs. The blood pressure in the lungs drops suddenly due to this. Then the blood starts to flow through the lungs via right heart. It no more need to pass via left atrium. These changes are natural consequence of the pressure changes in the lungs and heart chambers. The hole between both the atria get closed as a result. ( This looks simple to explain. It is simple. But the great question is, 'Who designed these simple things?' That means, 'Who designed the rules of Nature? The chances of every thing getting created by accident are very very remote. The only explanation is that the rules of nature are designed by "Somebody".)